print("条件判断##################################################start")
age = 20
if age >= 18:
    print('your age is', age)
    print('adult')

age = 3
if age >= 18:
    print('adult')
elif age >= 6:
    print('teenager')
else:
    print('kid')
# String转换整数int()函数
age = 20
if age >= 6:
    print('teenager')
elif age >= 18:
    print('adult')
else:
    print('kid')

s = input('birth: ')
birth = int(s)
if birth < 2000:
    print('00前')
else:
    print('00后')
print("条件判断##################################################end\n")